Re: Subjects are relative but do they represent anything real?

Posted by Dale on Mar 06, 2002 at 09:00

Re: Snatch the pebble, don't understand title or concept (dogrock)

Which is smaller; the paper or the ruler? Each observer says it is the other one. Both have a pocket watch. Which is running slower? Each observer says it is the other one. Has either gained weight? Both call the other fat. Each observer exists in a different reality.

Now we want to synchronize the realities. To do this one or the other has to accelerate to the other's velocity. Let's accelerate (decelerate) the ruler. Now the two observers see the same thing. All size differences have disappeared because both observers are now traveling at the same speed. Each observer pulls out their pocket watch and they are running at the same speed. They step on a scale and both agree as to the other's weight.

Is there anything left from the old realities? As far as a shape change, they were different and now they arenít. Both saw a smaller other and now they see the same. Maybe they could compare photographs but there is nothing permanent about shape. The weights were different and now they aren't. Where did the mass come from and where did it go? It didn't. Those were just different realities that no longer exist. Time, on the other hand, has a permanent artifact. Their watches reflect not only the current rate of passage but the accumulated passage since some previous agreed to point. The watches are now running at the same speed but they donít show the same elapsed time. The difference is the acceleration/deceleration . The one that has changed speed is the one that shows time ran slower. It works both ways. If the paper was stationary as the ruler passed and accelerated to catch up with the ruler, it would be the paperís watch that was behind.

Now, what happens if both accelerate to a common speed? The ruler slows and the paper accelerates. The sizes become equal and teh weights agree and the watches run at the same speed but which watch shows more time has passed? Oooooh!!! Oooooh!!! BRAIN CRAMP!!! BRAIN CRAMP!!! I occasionally get these when thinking relatively and often get them when thinking about quantum mechanics. I have to rest now. ;)

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